From nobody Fri Jun 19 13:06:08 2026 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BDC052AE78; Sat, 25 Apr 2026 17:37:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.19 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777138680; cv=none; b=eHXUYl4mwkooMhIGXsx+beM657QerNdlOo4h2Q+e7qNQfxR+dw9pu5JhEiwT7yopsVa8daYQVyf8N2vMqPGxbhWYrVtCfobD4QQoQ5F7sKcNb/vGBumMYTkUPeEEFbZ57nw0Wic6SzyRQL1vFMn31/OEdKXtuKvVJEiowb5LmOM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777138680; c=relaxed/simple; bh=+pdmtcon42VWElEZHR1aaLdDpfyPWhH24qOPGS4yq/A=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=jNtt0luToviJST/94p4xStMtgaOxcJQTGqYQJKpgIPFAb0EtVFb/SOTvB+lfituHe4VETDJe9BhdhSca8NNtVWLY/zCzBn/QXzY7ONxrvbv2ai3ltBeDRK+qoDfWzKdfwa7J72NrOFFR1aYwkM1yS7Pfn3dq/k/s9Wj0MqdItBM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=OmsFCtQS; arc=none smtp.client-ip=192.198.163.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="OmsFCtQS" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1777138679; x=1808674679; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=+pdmtcon42VWElEZHR1aaLdDpfyPWhH24qOPGS4yq/A=; b=OmsFCtQScaTWM70s/b+BDb2tEu0qkP3dmGtAdz+xUjaA2ghjMQGnBt2j jiyPu3U1h1qIPAy/LOllZwFMWAjvGBjNyaqotLBKP8c/eXKPl0+enzRgl 2ka/Hkoel09fN3it7pItsXmdnX3GvaV6JrMaQB/SCc15gS1Qd2CIU6fct IsblPY7AD1enNOdQT5bQ5oG6Yz323OlwQdB7RZilwY14g/thdagsN0cp0 x1r1WvV4HJ8XNG7rYs3vYL6f/3KyJr2Rhaq2jpYDLy1NxOOgqrL9qrjki NAsIV3QnRw2vugJnb/ABTeneVEDiS8aOWi8KMGIc5944/Vg8v5NTw97yr w==; X-CSE-ConnectionGUID: EehzlSfhRE+1QVosSU/YGg== X-CSE-MsgGUID: jDH5c9RvQUKPpRMwqmb3Ow== X-IronPort-AV: E=McAfee;i="6800,10657,11767"; a="77113488" X-IronPort-AV: E=Sophos;i="6.23,198,1770624000"; d="scan'208";a="77113488" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 Apr 2026 10:37:58 -0700 X-CSE-ConnectionGUID: LmmiCsbURaK8Q7+0k+O6tw== X-CSE-MsgGUID: E88mEBj/SgiBfVr38VYh9A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,198,1770624000"; d="scan'208";a="238233209" Received: from spandruv-desk.jf.intel.com ([10.54.55.20]) by fmviesa005.fm.intel.com with ESMTP; 25 Apr 2026 10:37:58 -0700 From: Srinivas Pandruvada To: hansg@kernel.org, ilpo.jarvinen@linux.intel.com Cc: platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org, Ali Ahmet MEMIS , Srinivas Pandruvada Subject: [PATCH] tools/power/x86/intel-speed-select: Harden daemon pidfile open Date: Sat, 25 Apr 2026 10:37:56 -0700 Message-ID: <20260425173756.862547-1-srinivas.pandruvada@linux.intel.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Ali Ahmet MEMIS Avoid symlink-based pidfile clobbering by opening the pidfile with O_NOFOLLOW and validating it with fstat() before locking/writing. The daemon currently uses a fixed pidfile path under /tmp. A local unprivileged user can pre-create a symlink at that path and cause a root-run daemon instance to write into an attacker-chosen file. Fixes: 7fd786dfbd2c ("tools/power/x86/intel-speed-select: OOB daemon mode") Signed-off-by: Ali Ahmet MEMIS Signed-off-by: Srinivas Pandruvada --- [Fixed commit message for long lines] tools/power/x86/intel-speed-select/isst-daemon.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/tools/power/x86/intel-speed-select/isst-daemon.c b/tools/power= /x86/intel-speed-select/isst-daemon.c index 66df21b2b573..acedb7432849 100644 --- a/tools/power/x86/intel-speed-select/isst-daemon.c +++ b/tools/power/x86/intel-speed-select/isst-daemon.c @@ -148,6 +148,7 @@ static void daemonize(char *rundir, char *pidfile) { int pid, sid, i; char str[10]; + struct stat st; struct sigaction sig_actions; sigset_t sig_set; int ret; @@ -200,11 +201,17 @@ static void daemonize(char *rundir, char *pidfile) if (ret =3D=3D -1) exit(EXIT_FAILURE); =20 - pid_file_handle =3D open(pidfile, O_RDWR | O_CREAT, 0600); + pid_file_handle =3D open(pidfile, O_RDWR | O_CREAT | O_NOFOLLOW, 0600); if (pid_file_handle =3D=3D -1) { /* Couldn't open lock file */ exit(1); } + + if (fstat(pid_file_handle, &st) =3D=3D -1) + exit(1); + + if (!S_ISREG(st.st_mode)) + exit(1); /* Try to lock file */ #ifdef LOCKF_SUPPORT if (lockf(pid_file_handle, F_TLOCK, 0) =3D=3D -1) { --=20 2.53.0